Thread control mechanism for sewing machines



Jan. 10, 1956 E. scHou ETAL THREAD CONTROL MECHANISM FOR SEWING MACHINES6 Sheets-Sheet 1 Filed NOV. 28, 1952 INVENTORS. EDGAR scnou BY SALVATORELIPPERE ATTORNEY Jan. 10, 1956 E. SCHOIJ ET AL 7 M THREAD CONTROLMECHANISM FOR SEWING MACHINES Filed Nov. 28, 1952 6 Sheets-Sheet 3 43FIG.3

/02 a I I r as y n [I 47;

INVENTORS.

F G. I l 69 7a EDGAR SOHO SAL VATORE L IPPERE ATTORNEY Jan. 10, 1956 ES.SCHOIJ ET AL 2,730,060

THREAD CONTROL MECHANISM FOR SEWING MACHINES Filed NOV. 28, 1952 6Sheets-Sheet 4 IN VEN TORS. EDGAR SCHOIJ SALVATORE LIPPE RE BY ATTORNEYJan 10, 19 E. SCHOIJ ETAL 2,730,060

THREAD CONTROL MECHANISM FOR SEWING MACHINES Filed NOV. 28, 1952 6Sheets-Sheet 5 IN VEN TORS. EDGAR SGHOIJ SALVATORE LIPPERE ATTORNE rfJan. 10, 1956 E. SCHOIJ ETAL 2,730,060

THREAD CONTROL MECHANISM FOR SEWING MACHINES Filed Nov. 28, 1952 eSheets-Sheet 6 #9 48 l- :50 FIGJ5 4 5' 14a F /49 I53 1 150 67 I52 I54/sa I52 I45 I47 I46 0 m N I57 A68 455 U 1 x40 40 D 9 1 IN VEN TORS.EDGAR SCHOIJ Y SALVATORE LIPPERE ATTORNEY THREAD CONTROL MECHANISM FORSEWING MACHINES Edgar Schoij, Chicago, and Salvatore Lippere, Berwyn,11]., assignors to Union Special Machine Company. Chicago, 111., acorporation of Illinois Application November 28, 1952, Serial No.323,098

Claims. (Cl. 112-162) The present invention relates to sewing machinesand more particularly to thread control in industrial sewing machinesused in the production of three thread overedge stitches along the freeedges of a plurality of superimposed pieces of work or along the freeedge of a single piece of work.

In a machine of the above type, the thread handling requirements are todeliver the correct amounts of each thread at the correct times andunder the correct tensions to the respective stitch forminginstrumentalities. It is particularly important in the formation ofcertain types of stitches, such as the Federal Standard Stitch Type 504,that the tension of the threads be such that, at the formation of astitch, they do not dig into or distort the work. In other words, it isdesirable that a relatively relaxed stitch be formed. At the same timeit is desirable that the threads be firmly drawn and uniformlypositioned to pro vide a neat effect and to leave no loose loops ofthread at the edge of the work.

Upon completion of a seaming operation, the usual practice is for theoperator to chain out somewhat at the trailing end of the work so thatthe material may be taken up and the chain cut. In order to facilitatehandling of the work, it is desirable that an elastic chain be produced.If an elastic chain is not produced, the operator must chain out anadditional amount to compensate for the inelasticity of the chain orrisk breaking one or more of the threads of the chain in pulling ittoward the chain cutter.

In accordance with the above, a primary object of the invention has been.to provide improved thread control means for a threethread overedgesewing machine.

More particularly, it has been an object of the invention to provideimproved thread control means for a three thread overedge sewing machinein which the correct amounts of each thread are delivered at the correcttimes and under the correct tensions to the respective stitch forminginstrumentalities.

Another object of the invention has been to provide thread. controldevices so constructed and coordinated as to be capable of producing aneat and firm, but relatively relaxed, three thread stitch which willnot dig into or otherwise distort the edges of the work.

A still further object of the invention has been to pro vide coordinatedthread control devices capable of producing a relatively elastic chain.

In accordance withthe invention, the foregoing objects have beenachieved by providing an overedge sewing machine having a reciprocableneedle, an under looper, an overedge looper, takeup mechanism foroperating on threads to the needle and loopers, and driving connectionsfor actuating the needle, the loopers and the takeup mechanism, with afirst threadguiding means for separately guiding the looper threads froma supply into association with the takeup mechanism therefor, and secondthread guiding means for separately guiding the looper threads from thetakeup mechanism therefor to the respective loopers, the latter threadguiding means being constructed and arranged to provide substantialresistance to passage A United States Patent 0 of both looper threadsbetween the takeup mechanism and the loopers and the driving connectionsbeingarranged to cause the takeup mechanism to engage the looper threadsas the loopers are operated away from the stitch forming point, wherebya substantial decrease in looper thread tension between the takeupmechanism and the looper is created during the interval in which thetakeup mechanism is imparting takeup action to the looper threads.

Further in accordance with the invention, novel means are provided fordrawing needle thread and looper threads from the supply, this meansbeing arranged to draw from the supply the amount of under looper threaddesired for each stitch before completely drawing from the supply thecorresponding amounts of overedge looper thread and needle thread.

Also in accordance with the invention, the novel thread takeup meansprovided permits adjustment of the location of the purl on the edge of astitch or seam by moving the thread eyelets but without adjustment ofthe thread tension means.

Other and further objects and features of the invention will appear fromthe following detailed description of an illustrative embodiment thereofshown in the appended drawings in which:

Fig. l is an end elevational view of an overedge sewing machineconstructed in accordance with the invention, a portion of the machineframe being broken away to illustrate the thread handiing mechanism;

Fig. 2 is a view, partly in front elevation and partly in verticalsection, of a portion of the overedge sewing machine of Fig. 1;

Fig. 3 is a plan view of a corresponding portion of the sewing machineof Fig. l, certain parts being broken away for clarity of illustrationof other parts;

Fig. 4 is a detail view of one of the thread tension devices embodied inthe machine;

Fig. 5 is an exploded view of the thread tension device shown in Fig. 4,showing the details of its component parts;

Fig. 6 is a perspective view of a thread guiding member embodied in theillustrative sewing machine;

Fig. 7 is a plan view of a portion of the sewing machine showingparticularly the looper thread takeup eyelets and the under looperthread guiding eyelets;

Figs. 7a and 7b are end views of certain of the parts shown in plan inFig. 7;

Fig. 8 is a detail view, in rear elevation, of the needle carrying armand associated parts;

Fig. 9 is a detail view, in side elevation, of the needle arm, thelooper thread takeup and cast-off means and related parts, the movingparts being shown at a time in the cycle of operation of the machinecorresponding to the commencement of the needle downward stroke;

Fig. 10 is a detail view similar to Fig. 9 with the parts in thepositions assumed when the looper thread cast-01f is about to push theunder looper thread ed the looper thread takeup;

Fig. 11 is a perspective view of the looper thread castoti and thelooper thread take-up showing the under looper thread as it is beingforced off the takeup and the overedge looper thread engaged by thetakeup;

Fig. 12 is a perspective view of the parts shown in Fig. 11 at a pointin the cycle immediately after the under looper thread has been cast-offwhile the overedge looper thread is still engaged by the looper threadtakeup;

Fig. 13 is a view, partly in front elevation and partly in section, ofthe parts shown in Fig. 12;

Fig. 14 is a perspective view of a thread stand arranged Referring nowto the drawings, the overedge sewing machine illustrated is of the typedisclosed in the copending patent application of Ned L. Wallenberg etal., Serial No. 196,104, filed November 17, 1950.

The machine is carried and largely enclosed by a frame (Figs. 1 and 2)which is of relatively low construction and is provided with a fiatbottom and a curved sloping top. This frame provides an enclosed chamberor housing portion 21 (Fig. 2) having a flat removable bottom plate 22secured to the frame by screws or the like. Chamber 21 is shown onlypartially in the drawings. For a detailed description of the mechanismscontained therein reference may be had to the above mentioned Wallenberget al. application. Chamber 21 is arranged to retain lubricant to asuitable level for the purpose of providing automatic lubrication of themajor wear receiving parts of the mechanism, in the manner set forth insaid pending application.

A vertical wall 23 at the left end of enclosed chamber 21 has anextension 24 at its lower end which partially encloses certain of thestitch forming and work feeding devices which must be provided exteriorof the enclosed chamber 21. Further partial enclosure of the chamberabove extension 24 is provided by a cloth plate 25 having downwardlyextending apron portions which normally conceal the stitch forming andwork feeding devices.

A main drive shaft 26 for the operating parts of the machine extendslongitudinally of the frame, substantially. along a line about midwaybetween the front and rear walls and midway between the planes of thebottom plate- 22 and the work supporting surface of cloth plate 25.Adjacent its left end, shaft 26 is supported by a pair of bearingsleeves 27 and 28 suitably mounted in the wall 23 of the frame. Asshown, the bearing sleeve 28 is preferably mounted in a retainer 29having a press fit in. an enlarged recess in the outer face of the wall23.

A support member (Figs. 1, 2, 3 and 14) mounted on frame 20 is arrangedto carry three thread tension devices 41, 42 and 43 for overedge looperthread 0, needle thread N, and under looper thread U, respectively.Tension device 41, as shown in Figs. 1, 2, 4 and 5, comprises a; screw44having a knurled head 45 and a threaded stem portion 46. This screwpasses through a hole in the top ofv support 40, through a bushingwasher 47, through two mating tension discs 48 and 49 and through atension spring 50. Threaded stem portion 46 engages a threaded hole inthecenter of a circular spring supporting plate 51 and is seated in anunthreaded recess or hole provided therefor in the-base 52 of supportmember 40. Plate 51 is provided with a slot 51A in one side thereofadapted to mate-with a pin 53.which is rigidly set in the base 52. Pin53 prevents plate 51 from turning with screw 44, so that as the. screwis turned, by means of its knurled head 45, the plate 51 is raised orlowered, depending upon which way thescrew 6: is turned. Raising of theplate 51 compresses spring and hence forces the tension discs 48 and 49under greater pressure into engagement with each other and, against thebushing washer 47. Similarly, lowering of:plate 51 decreases the tensionof spring 50, reducing the force exerted. on tension. discs 48 and 49.The tension discs regulate the tension on the thread passing betweenthem, and this thread tension is adjusted by turning head, 45.

Tension devices 42 and 43: may be identical with the device 41described. Support member 40' performs an important. function withrespect to each of the tension devices: in, that the side plate ofmember 40 acts as a shield covering. the tension. springs on the sidefacing the thread supply (Fig. 1), so that the thread cannot becaughtand broken in one of the. springs. The protection afforded therebyis of great significance at high sewing speeds. because, at such speeds,a substantial whipping action occurs between the thread supply and thetension discs.

The three threads 0'; N, and U come from their respective supplysources, which might be, for example, thread cones, and pass between therespective tension discs, as shown most clearly in Fig. 1 with respectto overedge looper thread 0. Inlet and outlet eyelets 54 and 55,respectively, are provided in member 40 for guiding each thread to andfrom a respective pair of tension discs, the thread being passed betweenthe tension discs somewhat to one side of the associated screw 44.

After passing through tension device 42, needle thread N passes throughan adjustable stationary guide eyelet 6% (Fig. 1), through a takeup 61adjustably mounted on a trimmer bar 62 by means of a screw 63cooperating with an elongated slot 64 in the takeup, thence successivelythrough two eyelets in a stationary guide bar 65 extending from a plate65a adjustably mounted on the machine frame by means of screws 66cooperating with slots 67 (Fig. 1), and finally to the eye of a curvedneedle 68. Needle 68 is carried in a socket 68' on an arm 69 mounted onand oscillated by a rock shaft 70. Rock shaft 7%) is operated bysuitable connect-ions (not shown in the drawings) with main shaft 26.Details of these connections, as well as other connections to the mainshaft 26 to be set forth hereinafter, may be found in the aforementionedWallenberg et al. applicatron.

The needle thread N tightens up and thread is drawn from the associatedthread cone on the down stroke of the needle 68. The takeup 61 isnormally carried as high on the. trimmer bar 62 as possible withoutcausing threadto be drawn from the cone on the up stroke of the needleand of the trimmer bar. The principal purpose in providing the takeup 61is to facilitate adjustment of needlethread N under various sewingconditions. Normally it only takes up a nominal amount of needle threadslack when the needle rises and delivers a nominal amount of needlethread when the needle'descendn'the operationof the trimmer bar beingsuitably coordinated with the. needle carrying arm and the takeup 61being suitably adjusted on the trimmer bar to accomplish this. However,takeup 61 may be adjusted on trimmer bar 62 so that it will take andgive more thread. In fact, takeup 61 may be adjusted to draw needlethread from theneedle thread cone should this prove desirable in meetingcertain sewing conditions. Trimmer bar 62, which carries takeup 61, alsocarries a movable trimmer blade which is adapted to cooperate with astationary trimmer blade (not shown) in shearing the edges of the workbetween successive advances, as is fully described in the saidWallenberg et al. application. Trimmer bar 62 is carried on a rock shaft76, suitably connected by means (not shown) to main shaft 26. Rock shaft76 and trim= rner bar 62 oscillate once upon each revolution of mainshaft. The trimmer bar oscillations are timed together with those ofneedle 68, so that the trimmer bar descends when the needle descends andvicever'sa.

The overedge or upper looper thread 0' coming from, its' supply sourcepasses through tension device 41 and then goes directly through alignedoveredge looper thread takeup eyelets 8 0 and 80' and then to andthrough a; vertical tube 81 mounted on the machine frame and finally tothe eye of an overedge looper 82 which is mounted: for reciprocation andoscillation on a looper shaft 83. Looper 82, is given a' combinedr'e'ciprocatory and oscillatory movement, by suitable connections such"as shown in said Wallenberg et al. application, which imparts to theactive end of the looper a spiral or'helical path. Overedge looper 82 isadapted to pass its thread through a loop of the under looper thread andthen carry the loop of its own thread upwardly and over the edge of thework into the path of the curved needle 68 while the latter is in itsuppermost position. Upon a subsequent oscillation of the needle 68,v itsthread will be carried through the loop of the-overedge looper thread.Thread takeup eyelets 80. and 80. are formed, respectively, in parallelbars 84 and 84' adjustably mounted on a bracket 85 by means of screw 86acting in elongated slot 87 and in a threaded hole through base orconnecting sleeve 88 for the bars 84 and 84' (Fig. 6). Base 88 and bars84 and 84 form a generally U-shaped bracket with aligned eyelet holes 80and 80, as is shown most clearly in Fig. 6. Bracket 85 is adjustablymounted on the machine frame by suitable means shown in Fig. 7. A footportion of the bracket is provided with an elongated slot 85a throughwhich is passed a screw 85b for fastening the bracket to the frame. Itwill be apparent that the guide bars 84 and 84' may be adjusted bothrotatably about the axis of the screw 86 and bodily with the latter inthe slot 87 Also the bracket 85 may be adjusted bodily and evenangularly on the frame to the extent permitted by slot 85a and screw85b. This enables correct positioning of the eyelets 80 and 80 for allsewing conditions.

The under or lower looper thread U extends from its thread supplythrough tension device 43, through a stationary eyelet 95 (Figs. 2 and3) adjustably mounted on the machine frame 20, through aligned underlooper 5 thread takeup eyelets 96 and 96' (Figs. 1 and 13) and throughspaced stationary eyelets 97 and 98 to an under looper 99. Eyelets 96and 96' are formed in a bracket similar to the one shown in Fig. 6 andcomprising apair of parallel bars 100 and 100 formed on a base 101having a hole adapted to receive a screw 102 which cooperates with anelongated slot 103 in bracket 85. It is evident that bars 100 and 100'are rotatably and laterally adjustable within bracket 85 and may beadjusted with the latter in the same manner as bars 84 and 84'. Eyelets97 and 98 are formed in end projections of a thread supporting member104 rigidly mounted on an adjustable guide member 105, as shown in Fig.7. Guide member 105 together with a second adjustable guide member 106maintains feed bars 107 and 108 in place.

Guide 106 is mounted on the machine frame by screws 109 and 110 whichact in an elongated slot 111 in a laterally extending arm of guide 106,as best shown in Fig. 7a. Provision of elongated slot 111 permitslateral adjustment of guide 106. Guide 105 is mounted on the machineframe by a screw 112 acting in an elongated slot 113 in guide 105, asbest shown in Fig. 7b. Provision of elongated slot 113 permits lateraladjustment of guide 105. It is evident that lateral adjustment of guide105 will also provide a slight lateral adjustment of eyelets 97 'and 98.

Under looper 99, which carries thread U, is mounted for reciprocation ona rod 110 actuated from main shaft 26 by suitable connections, not shownin the drawings but disclosed in said Wallenberg et a1. application.Looper 99 executes a simple reciprocatory movement along a straightline. Rod 110 is disposed at an acute angle, preferably between 20 and30 to the horizontal, and serves upon reciprocation to carry thethread-carrying eye of the under looper 99 from a position at the leftof the path of the needle and some distance below the cloth plate to apoint at the right of the path of the needle and substantially in theplane of the cloth plate 25 (Fig. 2). In such movement, the looper 99 isadapted to pass its thread through the loop of needle thread which is,at this time, presented below the cloth plate.

Both looper threads 0 and U are acted upon by a takeup member 115 whichis mounted on and oscillated by the needle bar rock shaft 70. Takeupmember 115, which is best illustrated in Figs. 8 through 13, comprisesan arm 116 clamped to the shaft 70, adjacent the needle carrying arm,and a bifurcated member 117 fastened to arm 116 by means of a screw 118.The branches of member 117 are divided into straight takeup portions 119and 119', which extend radially in relation to shaft 70, and curved orbent reentrant portions 120 and 120' which provide cast-off edges at thelower ends of portions 119 and 119 and surfaces to receive the cast-offthread. Portions 119 and 119 of takeup member 115 are arranged to movealong an arcuate path between eyelet bars 84 and 84' and between eyeletbars 100 and 100',

which, it will be remembered, are adjustably mounted on bracket 85. Acastoif member 125 is adjustably mounted on bracket by means of a screw126 acting in an elongated slot 127 in a rearward extension of member125. This extension is clamped within a slotted downward extension 128of bracket 85, the inner branch of which is threaded to receive thescrew 126. Cast-01f member 125 extends upwardly and outwardly to actbetween the forked takeup portions 119 and 119' of arm 117.

in the ascending portion of its oscillatory cycle, takeup member engagesunder looper thread U between eyelets 96 and 96 and carries the same ontakeup portions 119 and 119 (Fig. 11) until thread U is urged off of thesame by the lower edge of cast-off member 125. Cast-off member 125 caststhread U off the lower edges of takeup portions 119 and 119 and into thecurved portions and 120' as the takeup reaches about the positionindicated in Figs. 10 and 12. It will be observed that the arrangementof cast-off member prevents interference with overedge looper thread 0by under looper thread U. As takeup member 115 rises, the overedgelooper thread 0, which is normally resting on the upper edges ofcast-off member 125 (Fig. 2) is engaged by portions 119 and 119 (Figs.11 and 12) and is carried along or somewhat above the upper edge ofcast-01f member 125 and away from eyelets 80 and 80 (Fig. 13). Theextent of the takeup action on the thread 0 at different points in thecycle may be controlled in part by the member 125.

it should be observed that the overedge looper thread eyelet bars 84 and84, the under looper thread eyelet bars 100 and 100, and the cast-oifmember 125 are individually adjustable relative to their commonsupporting bracket 85. Furthermore, these thread controlling elementsare adjustable as a unit because, as has been noted hereinbefore,bracket 85 is adjustable relative to the machine frame.

A complete stitching cycle of the thread control and stitchinginstrumentalities will. now be described. Looper motions will beconsidered forward when a looper enters a thread triangle or loop andbackward when a looper sheds thread. Starting with needle 68 in itsuppermost position and ready to begin its descent, the overedge looper82 just reaches its uppermost and foremost position as the needle startsto descend, so that the needle will enter a thread triangle formed byoveredge looper 82 as the latter starts its return from this position.The under looper 99 has started its backward motion and sheds the needleloop seized thereby in the preceding cycle. The looper thread takeupmember 115, being fixed to the needle bar rock shaft 70, starts itsupward movement when needle 68 commences its downward travel. Atsubstantially the same time, needle thread takeup 61, which is mountedon trimmer bar 62, starts its downward motion. Just after the needleenters the overedge looper thread triangle but before it enters theWork, the looper thread takeup 115 engages the under looper thread U.Under looper thread U starts to be drawn from its supply while it isstill around the overedge looper 82. Most of the thread is drawn asunder looper thread U approaches and comes off the point of overedgelooper 82, although a little more thread is drawn as the under looperthread is pulled to the edge of the Work. Looper thread takeup 115engages the overedge looper thread 0 as the overedge looper 82 movesaway from the line of stitch formation. The under looper thread U iscast off from the overedge looper 82, pulled down to the stitch and thenis cast off takeup portions 119 and 119'. Following this step, the underlooper 99 starts forward to enter the needle thread loop and theoveredge looper tive. supply. cones. stops as the needlelfiS reachesthe. bottom of. its. stroke; The-under looper 99' enters the needlethread. loop as. the needle 68 begins to rise and the looper threadtakeup 1 15. is starting its backward motion. When needle. 68 is.approximately midway in its ascent, the overedge looper 82 enters thelower looper thread triangle, as shown in Fig; 2. The various stitchforming elements continueon to their original positions preparatory tocommencement of another stitch forming cycle. Feeding of the work, whichmay be performed as described in the said Wallenberg et al. application,takes place when the needleis out of the Work.

It will be observed that thepath. of overedge looper thread fromtension. device 41. to the eye of overedge looper 82 may conveniently bedivided into two portions, one extending from tension device 43to-talzeup-mernber 115 .and the other from takeup member 115 to theoveredge looper 82. A substantial frictional resistance to threadpassage is provided in the latter portion because ofthe thread guidingsurfaces provided therein and particularly because of thenumber, extent,and angular disposition ofthe. surfaces encountered. More specifically,during a portion of the ascent of takeup member 115, thread 0 is drawnfrom the associated supply cone or bobbin, through v tension device 41,eyelet 55 and eyelet 80 to takeup member 115. The thread controllingmeans from the takeup to the stitch are so arranged for the overedgelooper thread that at each thread contacting surface thereof when threadis being drawn from the supply, i. e., as the needle is approaching thebottom of its stroke, the tension is reduced on the side closest the.

stitch by the amount of friction created at each of said threadcontacting surfaces. This is accomplished by arranging such threadcontrol so that at each of the contacting surfaces thereof the threadmoves relative to the thread contacting surface away from the stitch. Asa result, the tension in thread 0 decreases from takeup member 115 tooveredge looper 82, providing a relatively low tension at the stitchwhereby the overedge looper thread 0 is laid onto the material in arelaxed manner. The overedge looper thread tension at the stitch ispreferably made about one third of the overedge looper thread tensionadjacent the takeup member. Decrease in thread tension at overedgelooper 82 is also aided by the fact that over-edge looper 82 is movingaway from the stitch point. when takeup member 115 contacts Because ofthe drop in tension between takeup member 115 and the overedge looper82, a relatively high tension may he provided at tension discs 48 and 49of tension device 41, so that the effect of thread variation is reduced.For example, if a tension at the stitch of one ounce is required and thetension at the takeup H5 is normally ounces, then a variation of oneounce at the tension discs 43 and 49'means only a variation of of anounce at the stitch. However, if the tension at the tension discsis'the' same as the tension at the stitch, then a variation of one ounceat the tension discs will cause azvari'ationof one ounce at the point ofstitch formation. Similarly, if the tension at the stitch is higher thanat the tension discs, then a variation at the tension discs will resultin a correspondingly higher variation at the stitch. A desirable effectof the reduction in thread tension atthe stitch and the permissibleincreased. tension at the tension discs 48 and 49 is the formation ofmore uniform stitches.

A decreasein tension of thread 0 from takeup member 115. to1 overedgelooper 82 reduces thread breakage and permits the use of poorer gradethreads. If the tension were to increase rather than decrease, thetension atthe tension discs would have to be substantially lower thanis. desirablev inorder. to preventexcessive; threadtbreakage".

between thetakeup and overedge-looper.

It. will be observed that the tension. in under looper" thread Udecreases between; takeup. member and; underlooper 9.9 because of' therelatively high frictional; resistanceof this: portion of the. lowerlooper'threadpath andbecause v of the direction of, threadmovementacross. each threadcontactingsurface. Thisaresult is aided.also;

bythe direction of. movement. of the looper duringthe:

takeup actiorrof. member 115. Thetension in the; lowcr thread at thestitchdoes-not have:as significant anreifect; on the stitch as isin the.case of the overedge looperthread' 0 because the. stitch tongue". 138onthe throat. plate 159 (Fig. l) helps keep the thread-.from;diggi ng.-intothe material. Since theneedle thread doesnotcome: over the edge ofthe materiahitisnottroublesomeinthis; respect. the needle thread N. atthe stitch. because. of difficulty; in; pulling up theneedlethread. Thistension should be-.-the-; highest in the system and the tension in'the.thread be+ tween thewtension. discsof device: 42=andthe needle68 shouldbe maintainedas closeto the maximum. aspossible to reduce effects ofthread variation; a

it should-be notedthat under looper threadU isrcomr pletely drawn.fronrits cone'or: bobbin'prior to the complete drawing. of.needlethreadN and overedge looper thread. 0. from theirrespective conesor'bobbins- Draw.- ingof. the needle thread.N=and the overedge looperthread; 0 does not: start untildrawing of. the-under looper; thread isalmost. complete, resulting in formationv of a. more; elastic chain.When the needle thread N and overedge thread. 0 are tightened up as theneedle 681gpes to the: bcttornof its stroke and. the under looperthread-U isnct tight,v the. stitch is not distorted. to any. extentbecause: the needle thread. N. is being pulled. up. to the material: anddoes notpulltheunderlooper thread U: away from the edge. The overedgelooper thread 0 is around the: needle 63 and cannot. pull the underlooper threadU oven the edge because. of thesnubbing action of theneedle 68, and because the under looper thread U is held to some extentby the needle thread N. When chainingthe under looperthread U tightensup, when. it is around the overedge looper. Prior to this time theneedlethreadN, has, slipped. off the under looper and. isrelatively slack. Thetight. under looper thread. U. coming off. the. overedge looper ispulled quickly tov the. edge of the throat", plate stitch tongue. andthe needle thread loop is located: at the edge of the stitch tongue.Thisaction causes-the needlethread to form in the chain in. an S-shapeon the under. surface of the stitch tongue so that sufficient needlethread; is pulled into the chain to make: it elastic. When sewing thetightening of the under looper thread U when the under thread is still.around. the overedge looper tends to,- pull" down the previously pulled.needle thread loop,.butsuch. pulling down is corrected. when the needle:descendsto. the bottom of its. stroke. The fact that the. under looper Uis slack when the needle thread- N is being pulled. up to its finalposition. permits a minimum amount of needle thread tension to be usedfor pulling upthe needle thread. An elastic chain facilitates feedingthe chainv out when no material is being sewn and also facilitatespulliug the material out to cut the chain, which reduces threadbreakage.

Referring now to Figs. 14 and 15, the thread stand illustrated has beenfound well suited. for supplying the three threads to the overedgesewing machine. The thread stand comprises an upright supporting rod 140which is mounted at its lower end, in suitable socket 141 provided in atable top 1.42. An adjustable clamp 143 is mounted on the upper end of arod 1.40.. A hori zontal arm or rod 144 is supported in clamp 143'.Adjacent, either end; and at the center of rod. 144: are mounted. threeupright supporting rods 145, 146 and 1.47, respec: tively, eachterminating in an inverted L-shaped head at the upper end thereof. Atthe free end. of each supporting it is desirableto provide amaximumtension; in

rod there is provided an S-shaped hook 148 adapted to fit into a hole149 of the associated rod and into a hole 150 of a respective conesupporting rod 151. Each of rods 151 is provided adjacent each extremitythereof with a collar 152. secured to rod 151 by set screws 153.Slidably mounted on each rod 151 between the limits provided by collars152 is a wood block 154 having a generally frustro-conical shape. Threadcones O, N, and U which supply, respectively, threads 0, N, and U, maybe placed upside down on the respective blocks 154. By jamming thethread cones on the respective blocks and against the upper collars 152,the cones are frictionally held to the blocks. When it is desired toremove a cone from the associated block, the cone may be pulleddownwardly and off the block, lower collar 152 retaining the block onthe rod 151. A C-shaped horizontal guide member 155 is mounted in rod144 and provided with thread guiding holes 156, 157 and 158 eachdisposed below a respective thread cone and adapted to receive and guidethreads 0, N, and U respectively.

While the invention has been described in a specific embodiment thereofand in a specific use, it should be understood that the invention is notlimited thereto for obvious modifications thereof will occur to thoseskilled in the art without departing from the spirit and scope of theinvention as set forth in the appended claims:

What is claimed is:

1. In an overedge sewing machine having a main drive shaft stitchforming means including a needle, an overedge looper and an underlooper, and connections from said shaft for operating said stitchforming means in coordination to form overedge stitches, the combinationof thread controlling devices for controlling the delivery of threadsfrom sources of supply to said stitch forming means, said devicesincluding a plurality of thread guiding means for each of the threadsdelivered to the needle, the overedge looper and the under looper, aplurality of thread takeup members arranged to act upon the severalthreads in the course of their delivery to said stitch forming means,and connections from said shaft for operating said takeup members insuch timed relation as to completely draw the thread delivered to saidunder looper from its source of supply before the threads delivered tosaid needle and said overedge looper are completely drawn from theirsources of supply, said takeup members being arranged to draw all ofsaid threads from their sources of supply during the latter part of thedownward movement of the neddle.

2. In an overedge sewing machine having a main drive shaft stitchforming means includin a needle, an overedge looper and an under looper,and connections from said shaft for operating said stitch forming meansin coordination to form overedge stitches, the combination of threadcontrolling devices for controlling the delivery of threads from sourcesof supply to said stitch forming means, said devices including aplurality of thread guiding means for each of the threads delivered tothe needle, the overedge looper and the under looper'and a plurality ofthread takeup members arranged to act upon the several threads in thecourse of their delivery to said stitch forming means, connections fromsaid shaft for operating said take up members, and thread tensioningmeans acting upon the several threads between their sourses of supplyand said takeup members, said devices and said means for operating saidstitch forming means and said take up members being constructed andarranged to exert the primary takeup action on the overedge looperthread as said looper is moving away from the point of stitch formationand as the path of said thread is being shortened from the point ofstitch formation to the nearest guide for said thread, so ,as to imparta substantially lower tension to the thread delivered to said overedgelooper at the point of stitch formation than adjacent the associatedtakeup member. i

3. An overedge sewing machine comprising a main shaft, a reciprocableneedle, an under looper, an overedge looper, means for drawing needlethread and looper threads from a supply, said means serving to draw offall of said threads from their sources of supply during the latter partof the downward movement of the needle and being arranged to completelydraw from the supply the amount of under looper thread desired. for eachstitch before completely drawing from the supply the correspondingamounts of overedge looper thread and needle thread, said meansincluding a takeup member for operating on both of the looper threads,and driving connections from said shaft for actuating said needle, saidloopers and said takeup member to effect said timing of their actions.

4. An overedge sewing machine comprising a reciprocable needle, an underlooper, an overedge looper, means for drawing needle thread and looperthreads from a supply, said means serving to draw thread from the supplyfor said needle and said loopers as the needle is descending and beingarranged to draw from the supply the amount of under looper threaddesired for each stitch before drawing from the supply the correspondingamounts of overedge looper thread and needle thread, and said meansincluding a needle thread takeup element arranged to cooperate with saidneedle in drawing thread from said supply, a takeup member having atakeup portion for engaging and drawing from said supply said underlooper thread and said overedge looper thread and having a cast-offthread receiving portion, said takeup member being arranged to draw mostof said under looper thread from said supply before drawing saidoveredge looper thread from said supply and to completely draw saidunder looper thread from said supply before completely drawing saidoveredge looper thread from said supply, a cast-off member arranged tocooperate with said takeup portion to cause said under looper thread tobe disengaged from said takeup portion and engaged by said cast-offthread receiving portion as said takeup member is moving in a directionto takeup thread, and driving connections for actuating said needle,said loopers, said takeup element and said takeup member in coordinatedrelation to effect said timing of their actions.

5, An overedge sewing machine comprising a reciprocable needle, an underlooper, an overedge looper, means for drawing needle thread and looperthreads from a supply, said means serving to draw thread from the supplyfor said needle and said loopers as the needle is descending and beingarranged to draw from the supply the amount of under looperthreaddesired for each stitch before drawing from the supply thecorresponding amounts of overedge looper thread and needle thread, andsaid means including a needle thread takeup element arranged tocooperate with said needle in drawing thread from said supply, a takeupmember having a takeup por: tion for engaigng and drawing from saidsupply said under looper thread and said overedge looper thread andhaving a cast-01f thread receiving portion, said takeup member beingarranged to draw most of said under looper thread from said supplybefore drawing said overedge looper thread from said supply and tocompletely draw said under looper thread from said supply beforecompletely drawing said overedge looper thread from said supply, acast-off member arranged to cooperate with said takeup portion to causesaid under looper thread to be disengaged from said takeup portion andengaged by said cast-off thread receiving portion as said take up memberis moving in a direction to take up thread, and driving connections foractuating said needle, said loopers, said takeup element, and saidtakeup member in coordinatedrelation to effect said timing of theiractions, said driving" connections including a rock shaftfor'reciprocating said needle and said takeup member. f

6. An overedge sewing machine comprising a recipro cable needle, anunder looper, an overedge looper,means fondrawingneedle: threadandloopenthreads from .a supplyasaidsmeansaserving: to ,drawthread; from,the supply.

forzsaid needletand said loopers as the needle .is descend ingandx-beingarranged ttocompletely: draw from the supply: the; amount ofunder looper. thread desiredqfor eachstitchbeforecompletely drawing fromthe supply, the .co,r-. responding. amounts of-overedge looper threadand needle thread, .and said means .includingatakeup mechanism for.operating;on-,the I looper; threads, driving connections for;

actuatingsaidtneedle, said loopersandsaid takeup mecha-.

nism,-., first: thread guidingmeansifor separately guidingthezlooperythreads fromthezsupply intoassociation with saidztakeup;mechanism, and secondthread guiding means. for separately guidingthe;looper threads from said takeupmechanism to the respective loopers,said latter tthread:

guiding-;mea-nsz being constructed and arranged to providesubstantialiresistance --to passage, of overedge looper thread betweensaid;.takeup.mechanism and the overedge looper. andbeing; arranged todeliver thread to the overedge looper-alongsuch agpath that said looperyields thread as saidtakeup mechanism, is imparting its primary takeupaction to the overedge looper thread, and said driving connections beingso timed as to cause said takeup mechanism, to; engage the overedgelooper thread as said overedge looper is operated awayfrom the stitchforming point whereby a substantially lower tension is impartedtothe-thread deliveredto theoveredge looper at the point ofstitchzformation than is, imparted thereto adjacent said takeupmechanism during the interval inwhich said takeupmechanism is-impartingtakeup action to said overedge looper thread.

7.v An overedge sewing machine comprising areciproeableneedle,anunderlooper, an overedge looper, atake up mechanismfor operating on threads to said loopers, driving connections-foractuating said needle, said loopers and. said, takeup mechanism, firstthread guiding means for separately guiding the looper threads from asupplyinto. association with said takeup mechanism, and second thread,guiding means for separately guiding the looper threads from saidtakeup. mechanism to the respective loopers, said. latter thread guidingmeans having a plurality of thread contacting surfaces and beingconstructed and arranged to provide substantial resistance to passageof. overedge looper thread, between said takeup mechanism and theoveredge looper and being arranged to deliver thread to theoveredgelooper along such a path that saidlooper yields, thread as said takeupmechanism is imparting its primary: takeup action to the overedgelooper, thread, and said driving connections being so timed. as to causesaid takeup mechanism to engage theoveredge looper tthread and to, drawthe same over the associated thread contactingsurfaces of said secondthread guiding means in directions. away from the stitch when saidoveredge looper thread is being drawn from its 1 29 31 h tionship of theseveral parts being such that. the: overedge looper thread tensionadjacent said takeup mechanism .is approximately three times the tensiontherein at the stitch.

8. An overedge sewing machine comprising a reciprocable needle, an underlooper, an. overedgelooper, a takeup member for operating on threads tosaid loopers, drivingconnections; for actuating: said needle, saidloopers and said takeup member, first thread guiding means forseparately guiding the looper threads from a supply into associationwith said takeup member, and second thread guiding means for separatelyguiding the looper threads from said takeup member to the respectiveloopers, said latter thread guiding means being constructed and ar-.ranged. to provide; substantial resistance to passage ofthe looperthreads between said takeup member and the re-. spective loopers andbeing arranged to, deliver threads to said, loopers along such pathsthat said loopers yield thread as said takeup member is, imparting itsprimary takeup action, to the looper threads, and saiddrivingconnections being so timed as to, cause said takeup member 12 toengage;v the overedge; looper threadassaid overedge looper-is operatedaway. fromthe. stitch forming point whereby asubstantial decrease, inoveredgelooper thread tension between saidtakeupmember andsaidoveredgelooper is provided during the interval in which said take:

up member is imparting takeup action to saidioveredgev looper thread.

9. An overedge sewingmachine comprising a recipro-v cable needle, anunder looper, an overedgelooper, aitaker. up member for operatingonthreads to said loopers, driv-, ing connections for actuating saidneedle, said loopersand said takeup member, first thread guiding meansfonsepa; rately'guiding the looper. threads from supply. means intoassociation with said takeup member, and second thread. guiding meansfor separately guiding the looper. threads from. said takeupmernber tothe. respective loopers, saidj latter thread guiding means. comprisinga. plu'raliti of thread guiding surfaces arranged. to carry thevoveredge looper thread and to guidethe same along. a path havingportions disposed at sharp angles relativeto "each other. between saidtakeup member and said overedge. looper thereby to provide substantialresistance to passage of overedge looper thread between said takeupmemberand the overedge looper, said second thread guidingmeans beingarranged also todeliver thread tofthe overedge looper along such a path.that said looper yieldsthread as said takeup member is imparting itsprimary takeup action to the overedge looper thread, and said drivingconnections being so timed as to cause said takeup member to engagetheoveredge looper thread and to drawthe same over said thread guidingsurfaces in directions away from the stitch. when said overedgelooperthread is being drawnfrom said supply whereby the tension in theoveredge looper thread. at the stitch is substantially-lower than thetension therein adjacent said takeup memberwhen said overedge looperthread isbeing drawn from said supply.

10. An overedge sewing-machine. comprising arecipro: cable needle, anunder looper, an overedge looper, a takeup member for operating onthreads to said loopers, saidtakeup member having a takeup portion forengaging said looper threads and for drawing the same from a supply andhaving a cast-off thread'receiving portion, a cast-off member sodisposed relative to said takeup member as to disengage the under looperthread from said takeup portion as said member is moving in its threadtake up direction and causing the same to be engaged by said cast-offthread receiving portion after the amountof under looper thread desiredfor a stitch has been drawn from the supply, driving connections foractuating said needle, said loopers and said takeup member, first threadguiding means for separately guiding the looper threads from said supplyinto association with said takeup member, and second thread guidingmeans for separately. guiding the looper threads from said takeup memberto the, respective loopers, said latter thread guiding means beingprovided with a plurality of thread guiding surfaces constructed andarranged to, provide substantial resistance to passage of overedgelooper thread between said takeup, member and the overedge looper, andsaid driving. con nections being so timed as to cause said takeup.member to engage the overedge looper thread and to draw the same oversaid thread guiding surfaces in directions away from the stitch whensaid overedge looper thread is being drawn from said supply whereby thetension in the over edge looper thread at the stitch is substantiallylower than the tension therein adjacent said takeup member when saidoveredge looper thread is being drawn from said 13 member so disposedrelative to said takeup member as to disengage the under looper threadfrom said takeup portion as said member is moving in its thread take updirection and causing the same to be engaged by said cast-off threadreceiving portion after the amount of under looper thread desired for astitch has been drawn from the supply, driving connections for actuatingsaid needle, said loopers and said takeup member, first thread guidingmeans for separately guiding the looper threads from said supply intoassociation with said takeup member, and second thread guiding means forseparately guiding the looper threads from said takeup member to therespective loopers, said latter thread guiding means comprising aplurality of thread guiding surfaces arranged to carry the overedgelooper thread and to guide the same along a path having portionsdisposed at sharp angles relative to each other between said takeupmember and said over edge looper thereby to provide substantialresistance to passage of overedge looper thread between said takeupmember and the overedge looper, and said driving connections being sotimed as to cause said takeup member to engage the overedge looperthread and to draw the same over said thread guiding surfaces indirections away from the stitch when said overedge looper thread isbeing drawn from said supply whereby the tension in the overedge looperthread at the stitch is substantially lower than the tension thereinadjacent said takeup member when said overedge looper thread is beingdrawn from said supply.

12. An overedge sewing machine comprising a reciprocable needle, anunder looper, an overedge looper, a takeup member for operating onthreads to said loopers, driving connections for actuating said needle,said loopers and said takeup member, first thread guiding means forseparately guiding the looper threads from a supply into associationwith said takeup member, said first thread guiding means including afirst takeup eyelet for the overedge looper thread and a second takeupeyelet for the under looper thread, said takeup member being arranged toengage said looper threads adjacent the respective takeup eyelets andhaving a generally straight takeup portion for engaging the looperthreads and drawing the same from a supply and having a re-entrantcast-off thread receiving portion, a stationary cast-off member disposedadjacent the respective takeup eyelets and so arranged relative to saidtakeup member as to cause disengagement of the under looper thread fromsaid takeup portion as said member is moving in its thread take updirection and to cause the same to be engaged by said cast-off threadreceiving portion after the amount of under looper thread desired for astitch has been drawn from the supply, and second thread guiding meansfor separately guiding the looper threads from said takeup member to therespective loopers, said second thread guiding means including third andfourth takeup eyelets for carrying said overedge looper thread and saidunder looper thread, respectively, and being spaced, respectively, fromsaid first and second takeup eyelets, said takeup member and saidcast-01f member being accommodated between said first and third takeupeyelets and between said second and fourth takeup eyelets, said secondthread guiding means being provided with a plurality of thread guidingsurfaces constructed and arranged to provide substantial resistance topassage of overedge looper thread between said takeup member and theoveredge looper, and said driving connections being so timed as to causesaid takeup member to engage the overedge looper thread and to draw thesame over said thread guiding surfaces in directions away from thestitch when said overedge looper thread isbeing drawn from said supplywhereby the tension in the overedge looper thread at the stitch issubstantially lower than the tension therein adjacent said third takeupeyelet when said takeup member is imparting takeup action to saidoveredge looper thread.

13. An overedge sewing machine comprising a recipro- 14 cable needle, anunder looper, an overedge looper, a takeup member for operating onthreads to said loopers, driving connections for actuating said needle,said loopers and said takeup member, first thread guiding means forseparately guiding the looper threads from a supply into associationwith said takeup member, said first thread guiding means including afirst takeup eyelet for the overedge looper thread and a second takeupeyelet for the under looper thread, said takeup member being arranged toengage said looper threads adjacent the respective takeup eyelets andhaving a generally straight takeup portion for engaging the looperthreads and drawing the same from a supply and having a re-entrantcast-off thread receiving portion, a stationary cast-off member disposedadjacent the respective takeup eyelets and being so arranged relative tosaid takeup member as to cause disengagement of the under looper threadfrom said takeup portion and to cause the same to be engaged by saidcast-oif thread receiving portion after the amount of under looperthread desired for a stitch has been drawn from the supply, and secondthread guiding means for separately guiding the looper threads from saidtake-up member to the respective loopers, said second thread guidingmeans including third and fourth takeup eyelets for carrying saidoveredge looper thread and said under looper thread, respectively, andbeing spaced, respectively, from said first and second takeup eyelets,said takeup member and said cast-off member being accommodated betweensaid first and third takeup eyelets and between said second and fourthtakeup eyelets, said second thread guiding means comprising a pluralityof thread guiding surfaces for said overedge looper thread includingsaid third takeup eyelet and a thread carrying tube located between saidthird eyelet and said overedge looper and being angularly disposedrelative to the path therebetween, said third eyelet and said tubeproviding a relatively high resistance path for passage of overedgelooper thread between said takeup member and the overedge looper, andsaid driving connections being so timed as to cause said takeup portionto engage the overedge looper thread and to draw the same over saidthread guiding surfaces in directions away from the stitch when saidoveredge looper thread is being drawn from said supply whereby thetension in the overedge looper thread at the stitch is substantiallylower than the tension therein adjacent said third takeup eyelet whensaid takeup member is imparting takeup action to said overedge looperthread.

14. An overedge sewing machine comprising a reciprocable needle, anunder looper, an overedge looper, takeup means for operating on threadsto said loopers, driving connections for actuating said needle, saidloopers and said takeup means, first thread guiding means for separatelyguiding the looper threads from a supply into association with saidtakeup member, adjustable thread tensioning means associated with saidfirst thread guiding means for tensioning the looper threads between thesupply and said takeup member, and second thread guiding means forseparately guiding the looper threads from said takeup member to therespective loopers, said second thread guiding means having a pluralityof thread guiding surfaces arranged to provide greater frictionalresistance to movement of said threads between said loopers and saidtakeup member than is provided by said thread guiding means to movementof threads between said tensioning means and said takeup member, andsaid loopers and guides being so arranged and said driving connectionsbeing so timed as to cause said takeup member to draw said looperthreads over said thread guiding surfaces in directions away from thestitch when said looper threads are being drawn from the supply wherebythe tensions in said looper threads at the stitch are substantiallylower than the tensions therein adjacent the takeup member when saidlooper threads are being drawn from the supply.

15: Ann oyeredgensewingsmachine comprising a. reciprocablesneefdle, anunder looper, an overedgeilooper, takeup meansyforhoperatinglon threadsto saidloopers, driving connections for actuating said needle, saidloopers. and said takeup means, firststhread guiding means forseparatelyaguiding the looper threads from a supply into associationwith saidtakeup. member, adjustable thread tensioningmeans associatedwith saidvfirst thread guiding means for .tensioning the loopervthreadsbetween the sup-' ply and said, takeup member, and second thread guidingmeanslfor separately guiding the looper threads from said takeupvmeanssto the respective loopers, saidsecond thread guiding meanscomprising a plurality of thread contact.- ing surfaces, arrangedtoprovide greater frictional resistance to movement of saidthreadsbetween said loopers and said takeup, member than'is provided bysaidtthread guiding means 'to movement ofthreads between said 16andrguidesrb eing so arranged'and said driving connections being sotimed that said overedge looper thread is drawn over the associatedthread contactingsurfaces' of said second thread guiding means indirections away from the stitch when said overedge looper thread isbeing drawn from said supply whereby the overedge looper 1988,051 RubelJan. 15, 1935 2,054,493: Ebert Sept. 15, 1936 2,157,373 was May9f, 19392,265,678 Summers et a1 Dec. 9,l

